The prices quoted are an opinion of the appraiser only. Market prices can change drastically as with any commodity.  Personal desire for different qualities in an artifact can cause the same artifact to be worth different amounts to each collector/buyer. The opinion here is just an estimate of value and not a guarantee of actual worth. This is not an authentication paper, the owner is representing this piece as an ancient artifact and all liability rests with him/her and holds the appraiser harmless.